With commit e77b0852 ("mm/mmu_gather: track page size with mmu
gather and force flush if page size change") we added the ability to
force a tlb flush when the page size change in a mmu_gather loop.  We
did that by checking for a page size change every time we added a page
to mmu_gather for lazy flush/remove.  We can improve that by moving the
page size change check early and not doing it every time we add a page.

This also helps us to do tlb flush when invalidating a range covering
dax mapping.  Wrt dax mapping we don't have a backing struct page and
hence we don't call tlb_remove_page, which earlier forced the tlb flush
on page size change.  Moving the page size change check earlier means we
will do the same even for dax mapping.

We also avoid doing this check on architecture other than powerpc.

In a later patch we will remove page size check from tlb_remove_page().

Link: http://lkml.kernel.org/r/20161026084839.27299-5-aneesh.kumar@linux.vnet.ibm.comSigned-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Before this patch, we used tlbiel, if we ever ran only on this core.
That was mostly derived from the nohash usage of the same. But is
incorrect, the ISA 3.0 clarifies tlbiel such that:

"All TLB entries that have all of the following properties are made
invalid on the thread executing the tlbiel instruction"

ie. tlbiel only invalidates TLB entries on the current thread. So if the
mm has been used on any other thread (aka. cpu) then we must broadcast
the invalidate.

This bug could lead to invalid TLB entries if a program runs on multiple
threads of a core.

Hence use tlbiel, if we only ever ran on only the current cpu.

Fixes: 1a472c9d ("powerpc/mm/radix: Add tlbflush routines")
Cc: stable@vger.kernel.org # v4.7+
Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Signed-off-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

On architectures with hardware broadcasting of TLB invalidation messages
, it makes sense to reduce the range of the mmu_gather structure when
unmapping page ranges based on the dirty address information passed to
tlb_remove_tlb_entry.

arm64 already does this by directly manipulating the start/end fields
of the gather structure, but this confuses the generic code which
does not expect these fields to change and can end up calculating
invalid, negative ranges when forcing a flush in zap_pte_range.

This patch moves the minimal range calculation out of the arm64 code
and into the generic implementation, simplifying zap_pte_range in the
process (which no longer needs to care about start/end, since they will
point to the appropriate ranges already). With the range being tracked
by core code, the need_flush flag is dropped in favour of checking that
the end of the range has actually been set.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>
Cc: Michal Simek <monstr@monstr.eu>
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

In case other architectures require RCU freed page-tables to implement
gup_fast() and software filled hashes and similar things, provide the
means to do so by moving the logic into generic code.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Requested-by: NDavid Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix up powerpc to the new mmu_gather stuff.

PPC has an extra batching queue to RCU free the actual pagetable
allocations, use the ARCH extentions for that for now.

For the ppc64_tlb_batch, which tracks the vaddrs to unhash from the
hardware hash-table, keep using per-cpu arrays but flush on context switch
and use a TLF bit to track the lazy_mmu state.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

That patch used to just add a hook to page table flushing but
pulling that string brought out a whole bunch of issues, so it
now does that and more:

 - We now make the RCU batching of page freeing SMP only, as I
believe it was intended initially. We make a few more things compile
to nothing on !CONFIG_SMP

 - Some macros are turned into functions, though that forced me to
out of line a few stuffs due to unsolvable include depenencies,
however it's probably better that way anyway, it's not -that-
critical code path.

 - 32-bit didn't call pte_free_finish() on tlb_flush() which means
that it wouldn't push out the batch to RCU for delayed freeing when
a bunch of page tables have been freed, they would just stay in there
until the batch gets full.

64-bit BookE will use that hook to maintain the virtually linear
page tables or the indirect entries in the TLB when using the
HW loader.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where <asm-powepc/...> was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Fixes this powerpc build error in 2.6.22-rc6-mm1 for powerpc 64 with
CONFIG_SWAP=n :

In file included from include2/asm/tlb.h:60,
                 from /home/compudj/git/linux-2.6-lttng/arch/powerpc/mm/init_64.
c:56:
/home/compudj/git/linux-2.6-lttng/include/asm-generic/tlb.h: In function 'tlb_flush_mmu':
/home/compudj/git/linux-2.6-lttng/include/asm-generic/tlb.h:76: error: implicit declaration of function 'release_pages'
/home/compudj/git/linux-2.6-lttng/include/asm-generic/tlb.h: In function 'tlb_remove_page':
/home/compudj/git/linux-2.6-lttng/include/asm-generic/tlb.h:105: error: implicit declaration of function 'page_cache_release'
make[2]: *** [arch/powerpc/mm/init_64.o] Error 1

release_pages is declared in linux/pagemap.h, but cannot be included in
linux/swap.h because of a sparc related comment:

/* only sparc can not include linux/pagemap.h in this file
 * so leave page_cache_release and release_pages undeclared... */
#define free_page_and_swap_cache(page) \
        page_cache_release(page)
#define free_pages_and_swap_cache(pages, nr) \
        release_pages((pages), (nr), 0);
Signed-off-by: NMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

I think we have a subtle race on ppc64 with the tlb batching.  The
common code expects tlb_flush() to actually flush any pending TLB
batch.  It does that because it delays all page freeing until after
tlb_flush() is called, in order to ensure no stale reference to
those pages exist in any TLB, thus causing potential access to
the freed pages.

However, our tlb_flush only triggers the RCU for freeing page
table pages, it does not currently trigger a flush of a pending
TLB/hash batch, which is, I think, an error.  This fixes it.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

The current tlb flush code on powerpc 64 bits has a subtle race since we
lost the page table lock due to the possible faulting in of new PTEs
after a previous one has been removed but before the corresponding hash
entry has been evicted, which can leads to all sort of fatal problems.

This patch reworks the batch code completely. It doesn't use the mmu_gather
stuff anymore. Instead, we use the lazy mmu hooks that were added by the
paravirt code. They have the nice property that the enter/leave lazy mmu
mode pair is always fully contained by the PTE lock for a given range
of PTEs. Thus we can guarantee that all batches are flushed on a given
CPU before it drops that lock.

We also generalize batching for any PTE update that require a flush.

Batching is now enabled on a CPU by arch_enter_lazy_mmu_mode() and
disabled by arch_leave_lazy_mmu_mode(). The code epects that this is
always contained within a PTE lock section so no preemption can happen
and no PTE insertion in that range from another CPU. When batching
is enabled on a CPU, every PTE updates that need a hash flush will
use the batch for that flush.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

include/asm-ppc/ had #ifdef __KERNEL__ in all header files that
are not meant for use by user space, include/asm-powerpc does
not have this yet.

This patch gets us a lot closer there. There are a few cases
where I was not sure, so I left them out. I have verified
that no CONFIG_* symbols are used outside of __KERNEL__
any more and that there are no obvious compile errors when
including any of the headers in user space libraries.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!